chem

• Complete d-subshells form colourless solutions
• Back titration is used to find the number of moles of a substance by reacting it with an excess volume of a reactant of known concentration
• Degenerate mean equal energy
• Primary standard needs a high gfm, doesnt absorb water from atmosphere
• Reason for multiple lines on emission spectra is many electron transitions possible
• A weak acid is partially dissociated into ions in an aqueous solution
• K is only affected by temperature
• principle quantum number is n
• angular momentum quantum number is l and relates to s, d, p, f orbitals
• ml is magentic quantum number and has values between negative 1 and 1
• ms is the spin quantum number and is either +1/2 or -1/2
• Pauli exclusion principle states no two electrons in the same atom can have the same quantum numbers
• Aufbau principle is electrons fill subshells in order of increasing energy
• Hunds rule is electrons fill each degenerate orbital single and with parallel spins, before pairing up
• Examples on monodentate ligands are nh3, h20, cl-, oh-, cn-
• examples of bidentate ligands are 1,2-diaminoethane and oxalate ions (c204 2-)
• the coordination number of an ion is the number of bonds it forms to other atoms
• example of hexadentate ligand is EDTA
• delta H is positive for forward reaction in endothermic reactions
• when acid donates a proton, the species left is the conjugate base
• when a base accepts a proton, the species formed is conjugate acid
• The dissociation constant for the ionisation of water is called the ionic product
• Nitric, sulfuric and hydrochloric are strong acids
• Sodium/Potassium Hydroxide are strong bases
• Ammonia and amino alkanes are weak bases
• in acid buffers, the solution contains a mixture of weak acid and its conjugate base
• in basic buffers, the solution contains a mixture of weak base and its conjugate acid
• the entropy of a perfect crystal at 0K is 0
• molecular orbitals formed by end-on overlap are called sigma bonds
• molecular orbitals formed by side-on overlap are called pi bonds
• hybridisation in alkanes is sp3
• hybridisation in alkenes is sp2
• hybridisation in alkynes is sp
• absorption of em energy can cause electrons to be promoted from the HOMO to the LUMO
• Chromophore is a group of atoms within a molecule that is responsible for absorption of visible light
• chromophores exist in molecules containing a conjugated system
• colour with lowest frequency in visible light spectrum is red
• highest frequency em wave is gamma
• atomic emission spectroscopy is used to determine quantitatively the concentration of elements in a sample
• H+ decreases when an aqueous solution of ethanoic acid is diluted